Interactive input systems that allow users to inject input (e.g. digital ink, mouse events etc.) into an application program using an active pointer (e.g. a pointer that emits light, sound or other signal), a passive pointer (e.g. a finger, cylinder or other suitable object) or other suitable input device such as for example, a mouse or trackball, are known. These interactive input systems include but are not limited to: touch systems comprising touch panels employing analog resistive or machine vision technology to register pointer input such as those disclosed in U.S. Pat. Nos. 5,448,263; 6,141,000; 6,337,681; 6,747,636; 6,803,906; 7,232,986; 7,236,162; and 7,274,356 assigned to SMART Technologies ULC of Calgary, Alberta, Canada, assignee of the subject application, the entire contents of which are incorporated by reference; touch systems comprising touch panels employing electromagnetic, capacitive, acoustic or other technologies to register pointer input; laptop and tablet personal computers (PCs); personal digital assistants (PDAs) and other handheld devices; and other similar devices.
Above-incorporated U.S. Pat. No. 6,803,906 to Morrison et al. discloses a touch system that employs machine vision to detect pointer interaction with a touch surface on which a computer-generated image is presented. A rectangular bezel or frame surrounds the touch surface and supports imaging devices in the form of digital cameras at its corners. The digital cameras have overlapping fields of view that encompass and look generally across the touch surface. The digital cameras acquire images looking across the touch surface from different vantages and generate image data. Image data acquired by the digital cameras is processed by on-board digital signal processors to determine if a pointer exists in the captured image data. When it is determined that a pointer exists in the captured image data, the digital signal processors convey pointer characteristic data to a master controller, which in turn processes the pointer characteristic data to determine the location of the pointer in (x,y) coordinates relative to the touch surface using triangulation. The pointer coordinates are conveyed to a computer executing one or more application programs. The computer uses the pointer coordinates to update the computer-generated image that is presented on the touch surface. Pointer contacts on the touch surface can therefore be recorded as writing or drawing or used to control execution of application programs executed by the computer.
Multi-touch interactive input systems that receive and process input from multiple pointers using machine vision are also known. One such type of multi-touch interactive input system exploits the well-known optical phenomenon of frustrated total internal reflection (FTIR). According to the general principles of FTIR, the total internal reflection (TIR) of light traveling through an optical waveguide is frustrated when an object such as a finger, pointer, pen tool etc. touches the optical waveguide surface, due to a change in the index of refraction of the optical waveguide, causing some light to escape from the optical waveguide at the touch point. In such multi-touch interactive input systems, the machine vision system captures images including light that escapes the optical waveguide, reflects off each pointer contacting the optical waveguide and then passes through the optical waveguide, and processes the images to identify the position of each pointer on the optical waveguide surface based on the point(s) of escaped light for use as input to application programs.
U.S. Patent Application Publication No. 2011/0050650 to McGibney et al., assigned to SMART Technologies ULC, discloses an interactive input system with improved signal-to noise ratio and an image capture method. The interactive input system comprises an optical waveguide associated with a display having a top surface with a diffuser for displaying images projected by a projector and also for contact by an object, such as a finger, pointer or the like. The interactive input system also includes two light sources. Light from a first light source is coupled into the optical waveguide and undergoes total internal reflection within the optical waveguide. Light from a second light source is directed towards a back surface of the optical waveguide opposite to its top surface. At least one imaging device, such as a camera, has a field of view looking at the back surface of the optical waveguide and captures image frames in a sequence with the first light source and the second light source on and off alternately. Pointer interactions with the top surface of the optical waveguide can be recorded as handwriting or drawing to control execution of an application program.
Other arrangements have also been considered. For example, U.S. Patent Application Publication No. 2010/010330 to Morrison et al., assigned to SMART Technologies ULC, discloses an image projecting method comprising determining the position of a projection surface within a projection zone of at least one projector based on at least one image of the projection surface, the projection zone being sized to encompass multiple surface positions and modifying video image data output to the at least one projector so that the projected image corresponds generally to the projection surface. In one embodiment, a camera mounted on a projector is used to determine the location of a user in front of the projection surface. The position of the projection surface is then adjusted according to the height of the user.
U.S. Patent Application Publication No. 2007/0273842 to Morrison et al., assigned to SMART Technologies ULC, discloses a method of inhibiting a subject's eyes from being exposed to projected light when the subject is positioned in front of a background on which an image is displayed. The method comprises capturing at least one image of the background including the displayed image, processing the captured image to detect the existence of the subject and to locate generally the subject and masking image data used by the projector to project the image corresponding to a region that encompasses at least the subject's eyes.
Researchers have also identified different proximity zones in social interaction. A description of the division and nature of different proximity zones is disclosed in the reference entitled “The Hidden Dimension” authored by Edward T. Hall, published in 1966. Hall has identified four distinct proximity zones, namely an intimate zone, a personal zone, a social zone and a public zone.
While above-mentioned prior art describes various approaches for receiving user input, limited functionality is available for adapting the operating mode of interactive input systems based on a user's proximity relative to the interactive surface. It is therefore an object of the following to provide a novel interactive input system and method.